1. Technical Field
The present disclosure relates to a semiconductor memory device, and, more particularly, to an internal voltage generating circuit of a semiconductor memory device.
2. Discussion of Related Art
In recent years, typical semiconductor memory devices convert a high external supply voltage into a low internal voltage. The semiconductor memory devices cannot perform reliable operations until an internal power supply voltage is stabilized in a predetermined period of time after application of an external power supply voltage VDD. Accordingly, the semiconductor memory devices require a stable constant voltage power source because the internal power supply voltage is used in main internal circuits, such as a peripheral logic circuit or a memory cell array, and can significantly affect the performance of the entire semiconductor memory device.
In particular, semiconductor memory devices used in portable electronic devices may include both a first internal power supply voltage generating circuit, which operates whenever an external power supply voltage is applied, and a second internal power supply voltage generating circuit, which operates in response to only an active command.
Since semiconductor memory devices can consume a large amount of current in an active mode, the first internal power supply voltage generating circuit needs to be configured to have high current drivability and a fast response speed. By contrast, since the semiconductor memory device consumes only a small amount current in a standby mode, the second internal power supply voltage generating circuit may be configured to have a lower current drivability and a slower response speed than the first internal power supply voltage generating circuit.
Further, semiconductor memory devices may perform various operations, such as an active operation, a read operation, or a precharge operation, in response to various external command signals. Since internal operations of the semiconductor memory devices vary in response to a command signal, their power dissipation also may vary in response to the command signal.